Eduprobe
Question:
A study was conducted to find out the concentration of sulphur dioxide in the air in parts per million (ppm) of a certain city. The data obtained for 30 days is as follows: 0.03 0.08 0.08 0.09 0.04 0.17 0.16 0.05 0.02 0.06 0.18 0.20 0.11 0.08 0.12 0.13 0.22 0.07 0.08 0.01 0.10 0.06 0.09 0.18 0.11 0.07 0.05 0.07 0.01 0.04 (i) Make a grouped frequency distribution table for this data with class intervals as 0.00-0.04, 0.04-0.08, and so on. (ii) For how many days, was the concentration of sulphur dioxide more than 0.11 parts per million?
Solution:
Concentration of sulphur dioxide (in ppm) | Frequency
0.00 - 0.04 | 4
0.04 - 0.08 | 9
0.08 - 0.12 | 9
0.12 - 0.16 | 2
0.16 - 0.20 | 4
0.20 - 0.24 | 2
Total | 30
(i) The above figure is the grouped frequency distribution
(ii) The number of days for which concentration of SO2 is more than 0.11 → 0.12-0.16, 0.16-0.20, 0.20-0.24 ∴ Total number of days = 2 + 4 + 2 = 8 days.